1. Field of the Invention
The present invention relates to information recording apparatuses and information recording methods. More particularly, the present invention relates to an information recording apparatus, such as a video camera or a still camera, which records not only captured image, such as moving images or still images, but also management information corresponding to the captured images and to an information recording method in the information recording apparatus.
2. Description of the Related Art
Some apparatuses, such as video cameras or still cameras, capturing and recording moving images or still images are configured to record management information corresponding to the captured image data in management information files. For example, information concerning the dates and times when the images are captured, thumbnail images, and text information indicating features of the captured images are recorded in the management information files. Such recording configuration of the management information in related art is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2006-66014.
A file in which the management information is recorded is called a content management file or an Audio Video (AV) index file. The file in which the management information is recorded is hereinafter referred to as the “content management file”, entity data resulting from capturing of a moving image or still image is hereinafter referred to as a “content”, and a file in which contents are recorded is hereinafter referred to as a “content file”.
Information recording apparatuses, such as video cameras or still cameras, which record contents, such as moving images or still images, on information recording media, such as hard disks or flash memories, set in advance the areas where the content management files are recorded before starting the recording of the contents, for example, in initialization of the recording media. The content management file set in each information recording apparatus is repeatedly accessed each time each content file is accessed. An occurrence of fragmentation in which the files included in the content management file are scattered on the recording media undesirably reduces the access rate. In order to avoid such a situation, the areas where the files in the content management file are recorded are collectively allocated to a certain section on the recording medium in the initialization of the recording medium.
Information recording apparatuses usually allocate predetermined sizes to the areas where the content management files are recorded and record temporary information, such as all zero, in the allocated areas.
It is sufficient for one content management file to have the maximum size in which the management information corresponding to the maximum number of contents recordable on the recording medium can be recorded. If the content management file becomes full when a new content is to be recorded and no more management information can be recorded, the size of the content management file is too small.
Accordingly, in the initialization of the recording medium, the area in which the management information corresponding to the maximum number of contents estimated on the basis of the capacity of the recording medium can be recorded is allocated to the content management file. If the recording medium is built in the information recording apparatus and it is not necessary for a user to replace the recording medium with another one, it is possible to set an appropriate size of the content management file when the apparatus is designed.
Since the recording medium is not replaced with another one in the case of the built-in recording medium, it is sufficient to set one size to the content management file. In addition, since the built-in recording medium has a higher capacity, it is not necessary to expand the content management file, that is, to vary (increase) the size of the content management file later if the content management file having the estimated maximum size is created in the initialization of the recording medium.
In contrast, when recording media removable from the information recording apparatuses by users are used, the recording media of different types have various capacities. Accordingly, the appropriate size of the content management file is varied in accordance with the capacity of the recording medium that is used.
There are cases in which image files have already been recorded on a recording medium but the content management file including the management information corresponding to the recorded image files is not recorded. In other words, some image recording apparatuses in the related art do not record the content management files. When a recording medium on which images are recorded by using such an image recording apparatus in the related art is loaded in an image pickup apparatus that records the content management file, there are cases where the user wants to additionally create the content management file with the image files being left on the recording medium. In such cases, it is not possible to calculate the appropriate size of the content management file by a method similar to that for the built-in recording medium.
There are cases where the free space corresponding to the calculated size of the content management file is not left on the removable media. In addition, there are cases where content files can be additionally recorded on a removable medium after some content files are deleted even if the removable medium initially has the content files recorded thereon and has smaller free space. In such cases, no more content can possibly be added because the space of the content management file becomes short. If such an event occurs, it is necessary to increase the size of the content management file.